Identification and Functional Analysis of PR Genes in Leaves from Variegated Tea Plant (Camellia sinensis)

Tea is a healthy beverage made from the leaves of the tea plant [Camellia sinensis(L.) O. Kuntze]. The tea plant is a perennial evergreen plant that is widely distributed in tropical and subtropical regions. PR proteins (pathogenesis-related proteins, PRs) are defense-related proteins induced under pathogenesis-related conditions. Currently, there are a few studies on PRs in plants. Tea leaf color mutants have been of wide interest to scientists as special materials. A tea plant displaying variegated spontaneous albinism found in a local tea plantation in Huangshan City, Anhui Province, China, was used as the material sample in this study. An analysis of preexisting transcriptomic and proteomic data revealed the significant upregulation of three classes of PRs. In order to investigate the correlation between PRs and variegated tea plants, a series of studies were conducted onPRgenes. The results revealed the identification of 17CsPR1, 3CsPR4and 31CsPR5genes in tea plants using bioinformatics methods, and their structures and promoter sequences. The expression of threePR1, twoPR4and onePR5genes was determined to be induced in stress treatment experiments involving mechanical damage, insect bites, low temperature treatment, and fungal infections. Additionally, the ribonuclease activity of CsPR4 was successfully verified. This is the first study to report the ribonuclease activity of CsPR4 in tea plants. The results can serve as a reference for future studies on PRs in tea plants, offering new insights into information on albinism in tea plants.Keywords:identification;function analysis;pathogenesis-related protein;variegated tea plants